Traffic markings convey information to drivers and pedestrians by providing exposed visible, reflective, colored and/or tactile surfaces that serve as indicia. In the past, such a function was typically accomplished by painting a traffic surface. Modern marking materials offer significant advantages over paint such as dramatically increased visibility and/or reflectance, improved durability, and temporary removable marking options. Examples of modern pavement marking materials are thermoplastic, pavement marking sheet materials, tapes and raised pavement markers.
Preformed and hot applied thermoplastic materials used as pavement markings or for other indicia possess many advantages compared to paints and other less durable markings. These materials can be used for years. Known materials using high friction aggregates on the surface to improve friction has been known. The surface applied aggregates provide good initial values, however as the surface is worn due to traffic, the skid resistance decreases. After surface layers containing anti-skid materials become worn out these aggregate materials loose their effectiveness and become slippery because they do not contain high friction particles (of sufficient size to provide good skid properties).
Current thermoplastics include the use of primarily polyamide resins which have been shown to be unstable and often disintegrate in the presence of alkaline (pH of 8 or greater) environments. Certain (often newer) concrete compositions can also often become caustic and more highly alkaline in the presence of moisture after precipitation weather events. Today's thermoplastic materials do not include alkaline resistant properties using ethylene vinyl acetate resins primarily due to the lack of understanding of the affects of alkalinity on long term durability. Preformed thermoplastic decorative patterned materials are currently deteriorating rapidly in the presence of these alkaline environments.
A review of these issues demonstrates the need for thermoplastic products that provide alkali resistance to marking products for installation on road surfaces and also ensures that the integrity of the product (and pattern if so desired) is maintained after installation.